The present invention relates to an adjusting device for a transmission, in particular for a motor vehicle transmission, with at least one movable adjusting element, the position of which is detected by at least one sensor, wherein a cam path is provided which has sections of different heights which are provided to be scanned mechanically by a scanning element coupled to the sensor, and wherein the cam path has at least one catch in which a latching element can engage.
Speed converters and also speed-torque converters and components thereof are in this context referred to by the term “transmission”, in particular motor vehicle main transmissions, clutches, etc. are referred to by the term.
For controlling of transmissions of this type, input signals, produced, for example, by an operator or a controller, are converted into a mechanical movement of parts of the transmission. For example, during a change of gear speed or transmission ratio of a motor vehicle transmission, a selection and a shifting direction can be detected, can first be converted into movements of a selector lever and of a shift lever and then corresponding parts of the transmission can be moved. Conversely, the movements or positions, for example of the selector lever and shift lever, and the further parts of the transmission, such as, for example, the position of the shift forks have to be sensed.
According to the prior art, displacement sensors are used for the controlling of vehicle transmissions. The displacement sensors usually have a linearly movable pin. In this case, the sensor pin is coupled, for example, to the shift shaft in such a manner that a translatory movement of the shift fork leads to a linear movement of the sensor pin. The sensor is usually arranged in the lower oil chamber of the transmission and therefore exposed to high temperature and media loadings. For this reason, use is usually made of inductive displacement sensors which are very robust. In the case of these inductive sensors, the sensor pin moves in the interior of a coil. A movement, for example, of the shift shaft brings about a movement of the sensor pin which, in turn, causes a change in inductance in the coil. As an alternative, according to the prior art the linear movement, which is to be sensed, of the shift shaft can be fed to the displacement sensor via a cam path. For this purpose, sections of different heights are provided on the cam path, with different heights corresponding to certain positions of the shift shaft. These different heights are detected by a suitably arranged linear displacement sensor.
At the same time, the movement of adjusting elements, such as, for example, a shift rod, in the generic adjusting devices is usually influenced by latching devices. For this purpose, a latching element which is movable in the direction of the adjusting element and is prestressed in said direction is generally provided in the form of a pin which engages in corresponding catches. Before a movement of the adjusting element that guides the latching pin out of one of these catches, a certain counterforce has to be overcome.
The invention provides an adjusting device for transmissions, which has as few components as possible.
The adjusting device according to the invention improves on the generic prior art, for example, in that the sensor and the latching element are designed as a common component. In this manner, elements which are provided for the sensor functionality can likewise be used for the latching functionality. Given an appropriate configuration of the sensor, this enables the number of components to be reduced. In particular, latching positions can be provided at different heights in different sections of the cam path. In this case, the corresponding position of the adjusting element can be detected in the particular latching position.
In a preferred embodiment, it is provided that the sensor has a movable sensor element which is coupled mechanically to the scanning element or is formed integrally therewith. A movement of the sensor element leads here to a changing output signal of the sensor. The use of a separate scanning element, for example in the form of a finger, therefore permits greater freedom of design in terms of fitting the sensor.
In another examplary embodiment, it is provided that the scanning element is prestressed in the direction of the cam path. As a result, the scanning element is in continuous mechanical contact with the cam path. The sensor can therefore reliably detect the instantaneous position or a change in position, which takes place at a particular instant, of the adjusting element, and at the same can secure the adjusting element in the latching positions provided.
Furthermore, in one embodiment, it can advantageously be provided that the scanning element simultaneously forms the latching element. In this manner, correct latching can be detected particularly reliably.
An advantageous embodiment arises in particular by the cam path being provided to be arranged at least in some sections in an oil chamber of a transmission. This is advantageous in many cases, since the adjusting elements to be overcome are located there.
Furthermore, the invention can advantageously be implemented in that the sensor is provided to be arranged at least in some sections outside an oil chamber of a transmission. The sensor can therefore be fitted outside an environment unfavorable for it and therefore a more cost-effective structural form and/or a structural form having greater reliability can be selected for the sensor. For example, the sensor may be integrated into the cover of a transmission. Only the lower side of the sensor is therefore in contact with the oil chamber and exposed to the corresponding high loadings there.
Furthermore, it can be provided in an advantageous manner that the cam path is coupled mechanically to the adjusting element or is arranged thereon. By using its scanning element, the sensor can thus detect the mechanical movement of the adjusting element, which movement is transmitted to the cam path, and can be secured by a catch in an appropriate position of the adjusting element. For example, the cam path may also be integrated directly into the shape of the adjusting element. This constitutes an only insignificantly higher outlay on construction and production.
In a particularly preferred embodiment, it is provided that the sections of the cam path of different heights are arranged two-dimensionally. As a result, two movement directions which are independent of each other or the instantaneous position of the adjusting element with respect to two independent movement directions can be detected by just one sensor and corresponding latching positions made available. In this case, for the unambiguous detection of each discrete position to be detected, each position can be assigned an unambiguous height on the two-dimensional cam path. As an alternative, however, a plurality of positions having an identical height may also be coded in order to form a group of positions which is to be treated identically in terms of control.
Furthermore, the invention can be implemented in such a manner that the adjusting element can execute both a translational and a rotational movement, with both an angular measurement and a linear displacement measurement taking place via the sensor. Such a combined detection of a linear displacement measurement and an angle size by a single sensor reduces the complexity of the adjusting device both with respect to the number of sensors and with respect to the outlay on evaluation.
A further embodiment is advantageously developed by a plurality of sensors being provided, said sensors being arranged at least essentially parallel to one another. The parallel orientation of a plurality of sensors makes the electric connection of the sensors easier structurally and simplifies the installation thereof.
In particular, the invention can preferably be implemented in such a manner that the angular positions of a selector lever and of a shift lever and the position of at least one shift fork of the transmission are detected with the plurality of sensors. All of the position information necessary for controlling the transmission can thereby be detected.
Furthermore, it is advantageous in particular that the plurality of sensors is assigned a common evaluation circuit or a plurality of least similar evaluation circuits. The use of at least similar evaluation circuits in as few as possible a number—in the ideal case only one evaluation circuit—results in a significant reduction of costs.
It is likewise preferably provided that the plurality of sensors is assigned a corresponding plurality of cam paths having sections of different heights and a corresponding plurality of scanning elements, with the cam paths being designed in such a manner that comparable stroke movements arise for the scanning elements. Thus, on account of the comparable stroke movements, the same sensors can be used in spite of the different movements carried out by the adjusting elements, which advantageously reduces the number of different components within the adjusting device.
The likewise advantageous embodiment makes provision for the sensor to be an inductive displacement sensor. Inductive displacement sensors are suitable in particular for use in environments with a high temperature and/or media loading and can detect both translational and rotational movements by the cam path.
The exemplary embodiments of the invention provide combining the detection of the position and of the movement direction of an adjusting element by the provision of a cam path with a securing of the adjusting element by provision of catches in or on the cam path. This makes it possible to reduce the number of components. Furthermore, two independent movement directions can be detected with one sensor with the aid of a two-dimensional cam path.
Further refinements and special features of the invention are set forth in the following description of preferred embodiments.